Lagging salaries have caused a shortage of mathematics and science teachers in the nation's school districts that will last through much of the 1980s, said an Iowa State University study released yesterday.

Starting salaries for math and science teachers are only about 50 to 60 percent of industry salaries for people trained in mathematics, computer science and science fields, even when adjusted for a nine-month teaching contract, said Trevor Howe, director of the university's college of education placement office.

Howe and Jack Gerlovich, an Iowa Department of Public Information science education consultant, surveyed education departments in 45 states in 1979-80 and in 1981-82. They said 40 state offices reported either a critical shortage or shortage of physics and mathematics teachers and 39 reported a critical shortage or shortage of chemistry teachers.

In New York, Dr. Stephen Willoughby, president of the National Council of Teachers of Mathematics, said the shortage threatens national defense and the economy. Many soldiers, he said, can't make math calculations needed to aim today's sophisticated guns in the right direction.

Willoughby, a New York University professor, said Germany and Japan, with ample supplies of math-competent people in their pipelines, are developing capability to outdistance America in this math-dependent high technology era